diff --git a/crates/engine/src/extensions/widgets.rs b/crates/engine/src/extensions/widgets.rs index 13c6088c4..efdd21414 100644 --- a/crates/engine/src/extensions/widgets.rs +++ b/crates/engine/src/extensions/widgets.rs @@ -41,6 +41,8 @@ const FIELD: &str = "figcraft.widget.field"; const HOVER: &str = "figcraft.widget.hover"; /// Images in a widget are at most this many pixels on a side. const MAX_IMAGE_SIDE: u32 = 4096; +/// All images of one widget together are at most this many pixels once decoded (four of the largest). +const MAX_IMAGES_PIXELS: u64 = 4 * 4096 * 4096; /// Whether `n` is a widget's own layer. pub fn is_widget(n: &Node) -> bool { @@ -259,8 +261,9 @@ fn build(s: &mut Session, plugin: &str, w: NodeId, r: &WidgetRender) -> Result<( _ => n.plugin_data.remove(MENU), }; set_hover(n, r.root.hover.as_ref()); + let mut pixels = 0; for c in &r.root.children { - add(doc, w, c, cmd)?; + add(doc, w, c, cmd, &mut pixels)?; } // An SVG brings as many layers as it describes. if doc.subtree(w).len() > MAX_NODES { @@ -271,7 +274,7 @@ fn build(s: &mut Session, plugin: &str, w: NodeId, r: &WidgetRender) -> Result<( } /// Add layer `d` (and what it holds) inside `parent`, locked. -fn add(doc: &mut Document, parent: NodeId, d: &WidgetNode, cmd: &str) -> Result<()> { +fn add(doc: &mut Document, parent: NodeId, d: &WidgetNode, cmd: &str, pixels: &mut u64) -> Result<()> { let (kind, name) = match d.kind { WidgetKind::Frame => (NodeKind::Frame, "Frame"), WidgetKind::Text => (NodeKind::Text(TextData { characters: d.text.clone(), ..TextData::default() }), "Text"), @@ -292,6 +295,16 @@ fn add(doc: &mut Document, parent: NodeId, d: &WidgetNode, cmd: &str) -> Result< if bytes.len() > MAX_IMAGE_BYTES { return Err(bad(cmd, format!("an image is larger than {} KB", MAX_IMAGE_BYTES / 1024))); } + // From the header, before anything is decoded: a small file can hold billions of pixels. + if let Some((w, h)) = figcraft_render::images::dimensions(&bytes) { + if w > MAX_IMAGE_SIDE || h > MAX_IMAGE_SIDE { + return Err(bad(cmd, format!("an image is larger than {MAX_IMAGE_SIDE} pixels on a side"))); + } + *pixels += u64::from(w) * u64::from(h); + if *pixels > MAX_IMAGES_PIXELS { + return Err(bad(cmd, format!("the images are larger than {MAX_IMAGES_PIXELS} pixels together"))); + } + } let (hash, iw, ih) = crate::cmd::create::add_readable_image(doc, bytes).map_err(|e| bad(cmd, e))?; if iw > MAX_IMAGE_SIDE || ih > MAX_IMAGE_SIDE { return Err(bad(cmd, format!("an image is larger than {MAX_IMAGE_SIDE} pixels on a side"))); @@ -302,7 +315,7 @@ fn add(doc: &mut Document, parent: NodeId, d: &WidgetNode, cmd: &str) -> Result< } doc.insert(n, parent, None)?; crate::cmd::props::apply(cmd, doc, id, &props(d, false))?; - d.children.iter().try_for_each(|c| add(doc, id, c, cmd)) + d.children.iter().try_for_each(|c| add(doc, id, c, cmd, pixels)) } /// Add SVG layer `d` inside `parent`: a frame of the picture's own size holding its layers, locked @@ -604,3 +617,32 @@ pub fn specs() -> Vec { spec!("widget.list", "List widgets", "{} → {widgets: [{id, plugin, name, page, state, targets, fields, menu}]}", false, list), ] } + +#[cfg(test)] +mod pixel_budget_tests { + use super::*; + use base64::Engine as _; + + /// A `side` x `side` blank PNG (a few KB however many pixels). + fn png(side: u32) -> String { + let pix = figcraft_render::Pixmap::new(side, side).unwrap(); + base64::engine::general_purpose::STANDARD.encode(figcraft_render::encode_png(&pix).unwrap()) + } + + #[test] + fn images_of_a_widget_share_a_decoded_pixel_budget() { + let mut doc = Document::new("t"); + let page = doc.first_page().unwrap(); + let data = png(4096); + let image = |i: usize| serde_json::from_value::(json!({"type": "image", "name": format!("I{i}"), "data": data})).unwrap(); + let mut pixels = 0; + for i in 0..4 { + add(&mut doc, page, &image(i), "widget.insert", &mut pixels).unwrap(); + } + let err = add(&mut doc, page, &image(4), "widget.insert", &mut pixels).unwrap_err().to_string(); + assert!(err.contains("together"), "{err}"); + // A header past the side limit is refused before it is decoded. + let wide = serde_json::from_value::(json!({"type": "image", "data": png(4097)})).unwrap(); + assert!(add(&mut doc, page, &wide, "widget.insert", &mut 0).unwrap_err().to_string().contains("pixels on a side")); + } +}